Estrogen Receptor positive breast cancer in postmenopausal women: the role of body composition and physical exercise

Breast cancer (BC) is the most commonly diagnosed cancer among women worldwide, 25 and the most common cause of cancer related-death. To date, it is still a challenge to estimate the 26 magnitude of the clinical impact of physical activity (PA) on those parameters corresponding sig-27 nificative changes in future BC risk and disease progression. However, studies conducted in the last 28 years highlight the role of PA not only as a protective factor for the development of ER+ breast 29 cancer, but in general also useful in the management of BC treatment as adjuvant to traditional 30 therapies. In this review we focused our attention on data obtained from human studies analysing, 31 at each level of disease prevention (i.e., primary, secondary, tertiary and quaternary), the positive 32 impact of PA/exercise in ER+ BC, a subtype representing approximately 70% of all BC diagnosis. 33 Moreover, given the importance of estrogen receptors and body composition (i.e., adipose tissue) 34 in this subtype of BC, an overview of their role will also be made throughout this review.